Heat-conductive luting material



Patented Sept. 7, 1943 [UNITED STATES PATENT OFFICE v I 2,329,113 'I a c HEAT-CONDUCTIVE LUTINGMATERIAL William C. Ferguson, St. Louis, Paul Sussenbach, Richmond Heights, and Cyril H. Smith, Clayton, Mo., assignors to Presstite Engineering Company, St. Louis, Mo., a corporation of. j

Missouri No Drawing. Application May 14,1941,

Serial No. 393,428 I 7 carat. (01. 260-734) This invention relates to heatrconducting luting material, and more particularly to an imdisadvantages accrue. As both the tubeand' the container wall are irregular in shape, only,

provement upon the invention disclosed inthe United States patent application of William C. Ferguson, et al., forHeat-conducting luting material, Serial No. 282,065, filed July 30, 1939, now Patent 2,311,526.

Among the'severalobjects of the invention may be notedthe provision of a}mastic -like;luting material which has incorporated therein .a jrelatively large percentage ,of earthy or. clay-like particles for heat-conductive purposes, whereby the, material is'adapted for use, for example, as

a plastic or mastic connecting material used for surrounding objects in respect to which: itis desired toconductheat eitherto or awayfrom said article, such as cooling or heatingcoils'; the provision of ja-materialof, the class described which is substantially odorless and which is' of which will be indicated in the following claims.

As made clear in said application, in the construction of ice cream cabinets, beverage coolers,

and like apparatus, the container can in these cabinets is most usually cooled by means of refrigerant which circulates in a copper tube which is conducted backand forth across the surface of the container. The efiectiveness of this 'arrangement depends upon the ability of the brine in the tube to absorb the heat from the interior of the cabinet. This efiectiveness is Very largely dependent upon contact between the copper tube and the outer face of the container.

The current practice is either to continuously solder such tubes to the cabinet, or to spot-Weld thin strips of metal to attach the tube to the container. The soldering procedure, although fairly satisfactory from-the mechanical and heat-transference standpoints, is disadvantageous both in the cost of the solder and in the labor cost incident to using the solder. With the spot welding procedure, which ischeaper, more A second example is as follows:

indifferent contact, however, is thereby secured. Consequently this method of attaching tubes'to the outer walls of the container is disadvantageous-in the poor heat conductive relationship v obtained between the tubes and the container.

The present invention provides a material of plastic characteristics, somewhat like a putty, for example, which exhibits strong adhesive qualities for the-metals of the tube and thecorb tainer wall, and which may be used in such massive quantities as to bring about a relatively large area of heat transmission between the tube and the container wall. r .A suitable composition for the purpose is as follows? i I Per cent by weight Item:

Bauxite-tailings ('14 mesh). 74.90 Mineral oil- (light grade, pale) 24.20 Rubber (crepe) .24 1 Stearic acid (preferably pressed two or 'moretimes', but not necessarily so) H 126 Carbon black a 40 In the" above example, the'rubber is first cut up and dispersed in the mineral oil at a temperatureof 1300" F. This maybe done in a dough mixer. "Therefsulting substance is mixed with. the "bauxite; 'stearic acid and carbon black in percentages indicated. The resulting material is of a mastic nature that it may be applied with a trowel orthe like, not unlike plaster.

weight Item: Per cent by I Bauxite (20 fmesh) 43310 Standard varnish-makers aluminum flakes 7.4.5 Graphite (approximately 300 mesh) 20.65 Motor. oil (S. A. E. 80)-"; 11.60 Mineral oil (light grade, pale) 16.44

Rubber. derivative (trade-name Pliolite,

for examplejun-milled) .1.. .46

As is known, Pliolite is a derivative obtained from rubber and is made by treating rubber with a reagent from the group consisting ofchlorostannic acid and halides of amphoteric metals;

For further details of its characteristics see The Rubber Age, vol.- 45, No. 1, of April 1939, pages 17-21; the Wilson et a1. Patent No. 2,216,362,

gallon of 14 pounds, and the second example has a weight per gallon of 13.5 pounds.

The following figures are useful in indicating. advantages of the invention. For example; on "a given test the heat flow from a bare pipe to a ing material being substantially permanently mastic, said rubber derivative comprising rubber treated with a reagent from the group consisting of chlorostannic acid and halides of amphoteric metals.

3; A ,Juting material comprising a mineral oil base, a minor proportion of a rubber compound dispersed throughout said base, and a major proportion of at least one substance selected from the group consisting of bauxite and bauxite tailings also distributed throughout said base, said luting material being substantially permanently connected plate was measured: .at 6.4 B. t. "ulpe'r I lineal foot per hour. By employing plastic with metal (aluminum) flake along the lines indicated in said prior patent application, a heat flow with respect to the same pipe was obtained of 19.4 B. t. u. per lineal foot per hour. When using the substance of the first example above given, that is, a substance wherein only bauxite is used as 'a heat-conducting solid, the heat transmission on the same pipe was 160 B. .t. 11.;per lineal -foot per hour. In the second example, in which bauxite and aluminum flakes werepused,a heat flow of 212 B. t. u. per lineal foot per hour was-obtained.

The above comparative figures show that the bauxite particles account for a large proportion of the heat-conductive eflect.

Advantages of the inventionare that .a highly heat-conductive material is obtained, the largest constituent of which is the cheapest kind of a substance, namely bauxite or bauxite tailings.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. I

As many changes could .be made inthe .abfove products without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not a limiting sense.

We claim:

-1. A permanently mastic luting material :comprising a mineral on base, and one substance "selected from the group consisting of bauxite and bauxite tailings, said substance being distributed throughout said base.

. 2. A luting material comprising a mineral oil base throughout which a rubber compound is dispersed, and a major proportion of at least one substance selected from the group consisting of bauxite and bauxite ta'ilings,.said substance being likewise distributed throughout said oil, said. lutmasti-c, said rubber derivative comprising rubber treated with a reagent from the group consisting "of c'hlorostannic acid and halides of'amphcteric metals.

, 4. A luting material comprising a mineral oil 7 [base throughout which a rubber compound is dispersed, and a major proportion of bauxite tailings and a minor proportion of stearic acid and carbon black dispersed throughout said oil, said luting material being substantially permanently mastic, said rubber derivative comprising rubber treated with a reagent from thegroup ,consi'stingIof chlorostannic acid and halides of I amphoteric metals. f. 5. A luting material comprising a mineral oil base throughout which a rubber compound is dispersed, and a major proportion of bauxite and graphite .and a minor proportion of aluminum flakes distributed throughout .said oil, said luting material being substantially permanently mastic, said rubber derivative; comprising rubber treated with a reagentlfrom the group consisting of chlorostannic acid and halides of amphoteric metals. f

6. LA permanently mastic 'luting, material comprising an inert stable non-volatile mineraloil base, graphite; one substance selected from the WILL AM c. FERGUSON. PAUL'SUSSENBACH. 'CYRIL H. SMITH. 

